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SQL Server - sys.database_principals

Relationship to sys.sysusers

sys.database_principals seems to list the same users as sys.sysusers. The following two queries return no record, at least on the Server and database I am currently working on: 
select name from sys.database_principals except
select name from sys.sysusers;

select name from sys.sysusers except
select name from sys.database_principals;

See also

server_principals
Fixed database roles can be queried with select … from sys.database_principals where is_fixed_role = 1.
The sys schema
SQL Server: login

Index

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